Field of Invention
The present invention relates to a magnetic suspension planar motor, and belongs to a field of electrical machine.
Description of Related Arts
Modern precision machining equipments and ultra-precision machining equipments urgently require planar driving devices having high response, high speed, and high precision, in machining, producing electronic products, mechanical handling, manufacturing instruments and meters for automation, even driving robots, etc. Usually the planar driving device is driven by rotating motors. Rotating motion is transferred to rectilinear motion by mechanical devices, such as belts and ball screw shafts. The mechanical device is complicated, and transmission accuracy and transmission speed are limited. In addition, the mechanical device is required to be adjusted frequently in process of using, which causes disadvantages of high cost, poor reliability, and big size.
Original planar driving device is directly driven by two linear motors. This kind of planar driving device has a stacked driving structure, which increases complexity of transmission system. The mode that low dimensional motion mechanisms are superposed to form a high dimensional motion mechanism is not changed essentially. The linear motor in the bottom layer carries total mass of the linear motor in the upper layer and other relevant mechanical components, so the precision of positioning and controlling is affected seriously. However, planar motion of the planar motor is directly generated by electromagnetic energy, so the planar motor has characteristic of high output density, low heat consumption, high speed, high accuracy, and high reliability. The middle conversion devices are omitted, which transfers rotating motion to rectilinear motion, and then to planar motion, so the controlled object can be integrated with the planar motor. The planar motor has advantages of quick response, high sensitivity, good servo ability, and simple structure.
According to the generating principle of the electromagnetic thrust of the planar motors, the planar motors can be divided into variable reluctance types, synchronous type, and inductive type, wherein the synchronous planar motor has good overall performance of simple structure, big thrust, high efficiency, quick response speed, etc, so the synchronous planar motor is widely applied in two-dimensional planar driving devices, especially in precise two-dimensional planar driving devices.
FIGS. 7˜8 show a structure of a conventional permanent magnet synchronous planar motor. The permanent magnet synchronous planar motor mainly comprises two parts, i.e., a stator and a mover. The working principle of the permanent magnet synchronous planar motor is similar to the working principle of three-phase rotating permanent magnet synchronous motor. The stator comprises an iron core, and four thrust windings provided perpendicularly to each other. Each of the thrust windings has three independent phrases. The thrust winding in the X direction is for driving the mover to move along the X direction. The thrust winding in the Y direction is for driving the mover to move along the Y direction. The mover comprises a mover platform, and four permanent magnet arrays. The permanent magnet arrays are arranged on the lower surface of the mover platform. The mover platform is able to realize positioning motions on the plane by controlling the corresponding current of the three-phase winding.
However, the permanent magnet synchronous planar motor has disadvantages of complicated motor structure, small range of planar motion, low using rate of windings, low thrust density, low system efficiency, etc.